In the 1931 case of Eastern Air Transport, Inc. v. South Carolina Tax Commission et al., the U.S. Supreme Court ruled in favor of Eastern Air Transport (EAT). The issue at hand was whether or not EAT, an interstate air carrier incorporated in Delaware and operating planes over several states including South Carolina, should be subject to taxation by individual states for property located within their borders but used exclusively for interstate commerce purposes. The court held that such a tax would violate the Commerce Clause of the Constitution which gives Congress exclusive power to regulate interstate commerce. Therefore, it concluded that EAT's airplanes were not subject to state taxation as they were instruments of interstate commerce.

In the dissenting opinion for Eastern Air Transport, Inc. v. South Carolina Tax Commission et al., Justice Stone argued that the tax imposed by South Carolina on Eastern Air Transport was not an undue burden on interstate commerce and therefore should be upheld. He contended that the tax was a reasonable charge for the use of state facilities and services, such as airports and landing fields, which were necessary for carrying out interstate air transportation business within its borders. Furthermore, he pointed out that other forms of transportation like railroads or motor vehicles engaged in interstate commerce are subject to similar taxes without violating Commerce Clause restrictions. Thus, he disagreed with majority's view that this taxation constituted an unconstitutional regulation of interstate commerce.